In case you haven't seen this, look at attachment.
This has been needed for awhile (controlling number of people on the river.)..........but of course the BLM gives no rationale for the # of permits they have decided to issue. And we all know what a joy recreation.gov is.
I would encourage you to e-mail the Prineville BLM office:
.........and ask them to show the data (on their website) they have gathered over the years on boat numbers, time of year, # of people, etc etc.
Right now, this is just a "big black box" in my opinion.